The order Cetacea includes the whales, dolphins and porpoises and comprise the mammals most fully adapted to aquatic life. It contains 81 known species organized in two suborders: Mysticeti (baleen whales) and Odontoceti (toothed whales, which includes dolphins and porpoises). The order contains several record breaking species, with the Blue Whale being the largest animal known, and the Orca being the most widely distributed animal.
Cetaceans evolved from land mammals that adapted to marine life about 50 million years ago. Over a period of a few millions of years during the Eocene, the cetaceans returned to the sea. Their body is fusiform (spindle-shaped), the forelimbs are modified into flippers, the tiny hindlimbs are vestigial and the tail has horizontal flukes. Cetaceans are nearly hairless, and are insulated by a thick layer of blubber.
Cetaceans inhabit all of the world's oceans, as well as some rivers in South America and Asia. Some species can be found across the globe.
Cetology is the branch of marine science associated with the study of cetaceans.
Dolphin drive hunting, also called dolphin drive fishing, is a method of huntingdolphins and occasionally other small cetaceans by driving them together with boats and then usually into a bay or onto a beach. Their escape is prevented by closing off the route to the open sea or ocean with boats and nets. Dolphins are hunted this way in several places around the world. The largest number of dolphins are hunted using this method in Japan, however the practice also occurs on the Solomon Islands, the Faroe Islands and Peru. Dolphins are mostly hunted and killed for their meat; some are captured and end up in dolphinariums.
Despite the controversial nature of the hunt resulting in international criticism and the possible health risk that the often polluted meat causes, many thousands of dolphins are killed in drive hunts each year.
26 August - Findings from the controversial Japanese whaling research program suggest that a loss of Antarctic sea ice due to increased temperatures has lowered whales' food supply, causing an overall decline in blubber. Read more...
...the male narwhal's tusk can be up to 3.5 metres in length which is over the size of an average female without a horn and weigh up to 10 kilograms.
...male narwhal(e)s tusk is the canine growing through the lip. Sometimes, the male will have 2 tusks but their number is small. Female narwhal(e) rarely have a tusk and if they do, it must be smaller than the males. Also,there is only 1 recorded case of a duel horned female narwhal(e)
...observations of cetaceans date back to at least the classical period in Greece, when fisherpeople made notches on the dorsal fins of dolphins entangled in nets in order to tell them apart years later.
...groups of bottlenose dolphins around the Australian Pacific have displayed basic tool use by wrapping pieces of sponge around their beaks to prevent abrasions. This is a display of a cognitive process similar to that of great apes.
Photo credit: Jaime Ramos, U.S. Antarctic Program, National Science Foundation
Spyhopping is the act of coming out of the water vertically and momentarily staying out of the water in a manner akin to a human treading water. A powerful individual can spyhop as much as half of its body out of the water. The reasons for spyhopping are likely to be similar to those of breaching. Further spyhops may well be used so that the whale can examine its surroundings above the surface — for instance to look at boats. For this a spyhop may be more useful than a breach, because the view is held steady for a longer period of time.